Electric welding.



J. A. SEEDE.

ELECTRIC WELDING.

APPLICATION FILED JAN. 9. I914.

1,225,509. Patented May 8, 1917.

Witnesses: I lrwventor:

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UNITED STATES PATENT OFFICE.

JOHN A. SEEDE, OF NISKAYUNA, NEW YORK, ASSIGN'OR T0 GENERAL ELECTRIG COMPANY, A CORPORATION OF NEW YORK.

ELECTRIC WELDING.

Specification of Letters Patent.

Application filed January 9, 1914. Serial No. 811,121.

7 '0 all "whom it may concern:

Be it known that I, JOHN A. Simon, a citizen of the United States, residing at Niskayuna, in the county of Schenectady, State of New York, have invented certain new and useful Improvements in Electric Welding, of which the following is a specification.

My invention relates to electric welding and the object of my invention is to secure suitable voltage control, particularly to secure a proper starting voltage and a proper continuing voltage which may be of equal values or of different values. It is especially adapted to electric resistance welding employing a generator principally for supplying that load.

In electric welding of many sorts, the

load changes are not only abrupt but also of considerable relative magnitude, changing almost instantaneously from no load to full load and vice versa. Alternating currents being often preferable, it is difficult to secure apparatus of such inherent regulation that it will supply the proper or desired voltages under the various conditions met with in its operation if its capacity is anything like the full load value. Further, certain welding operations require or are benefited by the application of different values of voltage at the beginning and during the progress of the operation. But not only must provision be made for securing these values of voltage which may or may not be different from each other, but provision should be made for securing the proper respective values, that is, provision should be made for changing or obtaining one value without affecting the other and vice versa. It is one ofthe obj ects of my invention to provide for these independently controllable values of voltage in asimple, efficient and effective manner.

One of the cases met with in which my invention is applicable is that of a resistance welding machine supplied by a generator, of which the load furnished by the welding machine is a considerable fraction of the total load thereon; the'no load voltage must be limitedto a value that can be applied to the work without injury thereto, and with the assumption of the load the voltage tends to fall, often to an undesirably low value. The circuit is generally a highly inductive one and the current being alternating, the generator cannot easily be compound wound; either a generator of high inherent the load is thrown on and o supplying a control circuit, that is, a circuit controlling the supply of energy to the electrodes of the welding machine, with a resistance member having two ad ustable portions and providing means for supplying current through one adjustable portion of the resistance at no load and through a different adjustable portion as soon as the load is thrown on the circuit. In the case of a single generator. supplying welding apparatus of something like the capacity of the generator, the field circuit of the generator may be the control circuit in which the resistance is inserted, and a solenoid in series with the generator armature may be used to control the short-circuiting of one of the adjustable resistance Jortions when the machine. The capacity of the generator, so long as it is sufficient to carry the required load, and

its inherent regulation, are thus rendered quite immaterial factors.

In the accompanying drawings I have illustrated diagrammatically a welding system involving two forms of my invention. Figure 1 illustrates my invention applied to a generator supplying a single welding machine. Fig. 2 illustrates a modification of the resistance member.

In Fig. 1 is illustrated a system which is particularly adapted for the case of a welding machine supplied by a single generator, the apparatus being arranged to give independent control of the voltage applied to the work during the welding operation and of the voltage impressed on the electrodes when out .of contact with the work. The alternating current generator 1 supplies the welding machine which includes the transformer 2 and the electrodes 3. In series between the primary winding of the transformer 2 and the armature of the generator 1 is the solenoid a for controlling the initial and welding voltages. A common form of regulating reactance 5 may be used ice for regulating the current supplied to the work in the usual manner. In series with the field 6 of the generator 1 is the controlling resistance 7 which, in this figure is divided into two portions 8 and 9; each portion is a rheostat oi? the common form having the arms or movable contacts 10 and 11. The core 12 of the solenoid t carries a conducting contact member 13. In its lower position this contact member 13 bridges the contacts It and in its upper position bridges the contacts 1:). Contacts 14: are in the shortcircuit 16, 1'7 between the arm 10 and the conductor 18, which with the conductor 19, supplies the excitation current to the field winding 6. The contacts 15 are in the shortcircuit 16, 20 between the conductor 18 and the rheostat arm 11. As will be apparent from the drawing, the core 12 of the solenoid and its bridging contact 13 are adapted to be raised by current passing between the armature of the generator and the transformer 2, and the core and solenoid are so constructed that the core and bridging con tact 13 are picked up at a low degree 01 working current, but not by the exciting current for the transformer; with no working current, the core and bridging contact 13 fall to the lower position illustrated. There may or may not be an appreciable interval between the time when the current reaches the operating value for the relay 4: and the bridging of the contacts 15 as best suits the particular occasion. When the contacts 1 1 are closed, the circuit through the field winding 6 is as follows: from the conductor 18 to the conductor 16, contacts 1% and 13, conductor 17 rheostat 10, a part of the resistance portion 8, resistance portion 9 and the field winding 6 back to the conductor 19. WVhen the contacts 15 are bridged, the circuit is from the conductor 18 to the conductor 16, the contacts 15 and 13, the conductor 20 and a part of the resistance portion 9, and through the field winding 6, back to the conductor 19.

The operation is as follows: Before energy is supplied to the work, the apparatus is in the general positions illustrated. The rheostat arm 10 is adjusted to such a position that the part of the resistance portion 8 not short-circuited by 16, 17, together with the resistance portion 9, so limits the excitation oi? the generator, that it impresses on the primary winding of the transformer 2, the proper voltage for the very begin ning of the welding. The rheostat arm 11 is so adjusted that the resistance between it and the right hand end of the portion 9 is sufficient to limit the excitation of the field winding 6, and hence the voltage of the armature to the proper load or working value. At the first passage of current through the work the solenoid 4t attracts its core 12, opening the contacts 1 1 and closing the contacts 15, which are then maintained closed until the welding operation ceases; when the welding operation ceases the contacts 14 are closed again. It will be apparent "from this that the no load voltage may be controlled by the rheostat arm 10 and that the load voltage may be independently controlled by the rheostat arm 11 and further that both are substantially independent of the capacity of the generatorand its inherent regulation.

Other suitable connections and forms ot the resistance may be employed without departing from my invention. Another form or resistance is illustrated in Fig. 2. The s lenoid 1, core 12, contacts 13, 1% and 15, and the conductors 17 and 20 are all related as in the construction illustrated in Fig. 1. The resistance 7, however, consists of a sin gle rheostat having two sets of stationary contacts attached to each tap and two arms 21 and insulated from each other. The conductor 17 is connected to the arm 21 and the conductor 20 to the arm 22. The operation of this construction is similar to the operation ot the system illustrated in Fi 1. This modified construction, however, has one advantage in that the no load resistance in the excitation circuit may be less than the load resistance. To accomplish this result the arm 21 must be placed to the right of the arm 22 rather than to the left as indicated in the drawing. In the system illustrated in Fig. 1 the no load excitation can only be equal to or less than that of the load excitation. It can never be greater than the load excitation as it may be with the modification illustrated in Fig. 2.

What I claim as new and desire to secure by Letters Patent of the United States, 1s:-

1. In an electric welding system including a source of energy, means for applying the energy to the work and a circuit controlling the supply of energy to said means, a resistance for said circuit, two contacts for completing the circuit through diiferent portions of said resistance and means operative upon energy being supplied to the work for breaking the circuit through one of said contacts and completing it through the other.

2. In an electric welding system including a source of energy, means for applying the energy to the work and a circuit controlling the supply of energy to said means, a resistance for said circuit, two contacts for completing the circuit through different portions of said resistance and means operative upon energy being supplied to the work for completing the circuit through one of said contacts, the circuit prior to the operation of said means being completed through the other of said contacts.

In an electric welding system including a source of energy, means for applying an electrical welding current to the work, a separate circuit controlling the supply of energy to said means, an adjustable resistance completing said separate circuit, and means operative upon energy being supplied to the work for removing an adjustable portion of said resistance from said circuit.

4L. In an electric welding system including a generator, a resistance, the field Winding circuit being completed through an adjustable portion thereof, and means operative upon energy being supplied to the work for completing the circuit through another adjustable portion thereof.

5. In an electric welding system including a generatonan adjustable resistance for the field winding circuit of the generator and means operative upon energy being supplied to the work for removing all but an adjustable portion of said resistance from the field circuit.

e'ner bein su J )lied to the work and for b is 7 reinserting said portion of said resistance when the work is discontinued.

In witness whereof, I have hereunto set my hand this 7th day of January 1914-.

" JOHN A. SEEDE.

Vitnesses:

BENJAMIN B. HULL, MARGARET'E. WOOLLEY.

Copies of this patent mav be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. G. 

